A. Field of Invention
The invention relates to the use of isotopes to provide information to an article.
B. Description of the Prior Art
As a result of technology advances in reproduction techniques, many articles have become vulnerable to counterfeiting. This problem is particularly acute for items such as credit cards, compact discs, certificates, passports, identification cards, designer fashion accessories and clothing. In addition, an even more serious problem is the counterfeiting of currency, bank notes and other financial paper. A related problem is the unauthorized use of a financial item, such as a credit card, a registered security or an identity document.
Many techniques have been developed for labeling articles to prevent counterfeiting or fraudulent use. Techniques such as holograms on credit cards and magnetic coding on various articles have been in use for some time. These prior art techniques have been less than fully effective either because the counterfeiters have found ways to duplicate the label, or the apparatus for detecting the label and verifying its authenticity has been too expensive or cumbersome to be accepted for widespread use.
U.S. Pat. Nos. 4,742,340 and 4,862,143 teach the use of a y-ray radiation technique to detect counterfeit articles by labeling the articles with an enriched isotope such as iron-57, tin-119 or europium-151. However, this method requires a xcex3-ray source and xcex3-ray detector, which are perceived to be too hazardous for general use.
It is an object of certain embodiments of the present invention to provide a labeling composition for associating information with an article, which cannot be easily duplicated.
It is also an object of certain embodiments of the present invention to provide a method to obtain information about an article, which is fast, inexpensive and simple, yet provides a high level of security against fraud, counterfeiting or duplication.
It is also an object of certain embodiments of the present invention to provide an article including a label which can be easily read to provide information about the article, yet provides a high level of security against counterfeiting, fraud or duplication.
These and other objects of the invention will be apparent from the summary and detailed description, which follow.
In a first aspect, the present invention provides a composition for labeling an article that includes at least two isotopes of the same element at a predetermined abundance ratio.
In a second aspect, the present invention relates to a method for labeling an article with at least two isotopes of the same element and detecting the abundances and/or abundance ratio of the at least two isotopes of the same element to obtain information about the article.
In a third aspect, the present invention relates to an article labeled with at least two isotopes of the same element to thereby associate information about the article with the article by virtue of the isotope-containing label.